MAF-Keep it or ditch it! Explain why=>
Originally Posted by onfire
I have seen a stock screened ls1 maf become an inlet restriction at 17psi. Cost about 1.5 psi pressure drop....before and after pressure taps....
I believe I'll keep my ol 3bar. Starts easy, idles well and holds commanded AF at whatever boost I'm at....that's all I can ask for.....
I believe I'll keep my ol 3bar. Starts easy, idles well and holds commanded AF at whatever boost I'm at....that's all I can ask for.....
sometimes I too get frustrated with maf on the top end, but it just gives you more of a reason to understand it I guess. I was playing around with my truck tonight as well, and the 2 bar section is a nice thing to have, its just a matter of weather I like to fail the maf or run it all the way.
Rick
Originally Posted by mahhddgtp
But what would be the gains of going MAF?
LEts see, the pcm is pretty much half written for the maf, so alot of tables still rely on it. Hot starts are sometimes better, idle and part throttle transitions can be better. Day to day changes in temp also dont affect the MAF like an open loop tune does. So some things are nice, and yes, I like open loop tunes as well, but would take a good MAF tune any day.
Rick
Maf s do work and we still have 700+rwhp cars running them.
For this app. and alot of FI app,s I prefer 2/3bar SD tunes. It will run alot better in quicker time. The downfall is that it takes time to get perfect.I just finished my truck and it's perfect at 14.5-1 at part throttle and 11-8 A/F at WOT. Does not change at all in different weather/altitude but it took time.Throttle response is alot better than the perfect Maf tune I did without FI.
For this app. and alot of FI app,s I prefer 2/3bar SD tunes. It will run alot better in quicker time. The downfall is that it takes time to get perfect.I just finished my truck and it's perfect at 14.5-1 at part throttle and 11-8 A/F at WOT. Does not change at all in different weather/altitude but it took time.Throttle response is alot better than the perfect Maf tune I did without FI.
Originally Posted by Slowhawk
Maf s do work and we still have 700+rwhp cars running them.
For this app. and alot of FI app,s I prefer 2/3bar SD tunes. It will run alot better in quicker time. The downfall is that it takes time to get perfect.I just finished my truck and it's perfect at 14.5-1 at part throttle and 11-8 A/F at WOT. Does not change at all in different weather/altitude but it took time.Throttle response is alot better than the perfect Maf tune I did without FI.
For this app. and alot of FI app,s I prefer 2/3bar SD tunes. It will run alot better in quicker time. The downfall is that it takes time to get perfect.I just finished my truck and it's perfect at 14.5-1 at part throttle and 11-8 A/F at WOT. Does not change at all in different weather/altitude but it took time.Throttle response is alot better than the perfect Maf tune I did without FI.
Yes, a good SD tune as well is fun to drive. Because my dyno can hold load and steady state very well, its easy to build a VE table. But I still dont like sending alot of guys out of the shop with SD tunes. IF I know they can handle it, then I will. Other than that, its a MAF tune. My truck right now is using a hybrid tune, or something along the way.Rick
Quick question, Rick. If I reset my codes while the engine is running, the car has a noticeable stumble as it first fails the maf, then it runs in SD fine. I haven't tried what you are talking about yet, but isn't there a noticeable fueling problem as the MAF fails high under boost? I plan on keeping the MAF on my whippled work truck, even with a 2bar tune, because it isn't maxed out yet. However, I never thought of trying that with my car that will max out the MAF. Also, once the MAF fail code is set, doesn't it stay that way until you reset codes. Or does the MAF begin to operate again after the high freq fail condition is no longer met? I would just test this for myself, but it seems redundant if someone already knows the answers.
Originally Posted by gametech
Quick question, Rick. If I reset my codes while the engine is running, the car has a noticeable stumble as it first fails the maf, then it runs in SD fine. I haven't tried what you are talking about yet, but isn't there a noticeable fueling problem as the MAF fails high under boost? I plan on keeping the MAF on my whippled work truck, even with a 2bar tune, because it isn't maxed out yet. However, I never thought of trying that with my car that will max out the MAF. Also, once the MAF fail code is set, doesn't it stay that way until you reset codes. Or does the MAF begin to operate again after the high freq fail condition is no longer met? I would just test this for myself, but it seems redundant if someone already knows the answers.
Once you come back down, you actually go back into maf operation. Just make sure your VE table is close enough to your maf table, so that way the transitions are good. This should get you going.Rick
My question was purely academic, as I have no need to run a maxed MAF, but thank you for the response. I just thought that in the unusual case of the search function working, this info should be available.
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The problem I have with the maf is that it doesnt max out in 1st gear because it doesnt spool well being an sts w/ non wrapped exhaust and headers. However in 2nd and 3rd gear it does max out as 4500rpms. With the converter as soon as I hit 2nd its at 4500rpms and running off the pe and maxed maf..
This causes it to run 10.5 all the way through 1st gear and then in 2nd and 3rd it gets to 11.5 which is where I wat it. What do I need to do to fix this?
I have the 2 bar map sensor but have installed it yet. I will probably wait until I get the aps twin turbo kit and then do it then and start working on SD tuning. I have done SD tunes for my car when it was n/a and liked them very much more than the maf. Seemed to have better throttle responce and the fuel trims stayed in line much better. Got 5mpg better too.
Maybe its just easier to tune than a maf for me i dunno but that was my results.. I calibrated my maf as well and didnt help much.
This causes it to run 10.5 all the way through 1st gear and then in 2nd and 3rd it gets to 11.5 which is where I wat it. What do I need to do to fix this?
I have the 2 bar map sensor but have installed it yet. I will probably wait until I get the aps twin turbo kit and then do it then and start working on SD tuning. I have done SD tunes for my car when it was n/a and liked them very much more than the maf. Seemed to have better throttle responce and the fuel trims stayed in line much better. Got 5mpg better too.
Maybe its just easier to tune than a maf for me i dunno but that was my results.. I calibrated my maf as well and didnt help much.
